Multiple action thermostat



Dec. 5'; gq H, DAWS 2,101,637

MULTIPLE ACTION THERMOSTAT Fild Aug. 23, 1935 Patented De'c. 7, 1937UNITED STATES PATENT OFFICE 16 Claims.

This invention relates to multiple action thermostats and in itsapplication to automatic thermoelectric fire alarms the principle hereininvolved is illustrated and described in the modi- `5 ed ystructures ofmy applications for United States patents given Serial Number 732,172,led June 23, 1934, and Serial Number 8,776, led February 28, 1935. 'Ihisapplication is a continuation in part of my two said co-pending applilcations.

The present invention has numerous applications or uses and issusceptible of many modifications other than those just mentioned andthose shown and described herein without avoidl ing the spirit of thediscovery,

When used as a local detector of accidental fires in conjunction withdistant signals or annunciators in circuit therewith the Xed thermostatwould be adjusted with micromatic accuracy to function in its expansiblemovement at any predetermined temperature ranging from say `60 F. to 160F., but preferably is factory set at 110 F. for household, hotel andother like usages where the device is designed to give timely warning ofthe impending danger.

usages just named the rate-of-rise or quick-acting thermostat, in eventof a fast lire, would function in advance and independently of the xedthermostat and generally within from one to ve seconds from the time ofthe starting of this most dangerous form of accidental fire. Thelowering temperature thermostat acts independently of both the xed andthe rate-of-rise thermostats, all as will now be more particularlydescribed. y

In the accompanying drawing like numerals of reference thereon indicatecorresponding parts which appear in two or more of the views, wheremFig. l is a perspective View of my round form of multiple actionthermostat with the casing or cover in operative position.

Fig. 2 is a plan view of the interior of the structure below lines 2-2of Fig. 3.

Fig. 3 is a transverse vertical section of Fig. l.

Fig. 4 is a perspective View of my multiple action thermostat arrangedin a casing of rectangular shape with several of `the parts shown inFigs. l, 2, and 3 omitted.

Fig. 5 is a plan view of the structure of Fig. 4

with the cover removed in order to show clearly the interior parts.

Fig. 6 is a bottom view of the structure of Figs. 4 and 5.v

Referring specifically to the round form of In the" mydevice as by Figs.1, 2, 3, I provide a cupshaped casing I 0, which is preferably made ofinsulating material, such as molded Bakelite, provided with a cover Il,preferably oi stamped out sheet Bakelite, and secured by the screws l Ia5 to the casing l0. The widely spaced holes I Ib and the closelyarranged series or' holes Hc are .stamped thru the cover ll in the sameoperation which punches the holes therein for sc'rews lla, and blanksout the cover. In the bottom of the 10 casing l0 (see Fig. 3) is moldedthe closely arranged series of holes IDU which are in vertical registrywith the holes llc of the cover li.

What I term the rate-of-rise or the quick-acting thermostat comprisesmainly the arch shaped l5 and relatively thin bimetal blade l2 and itscoacting parts, as will now be more particularly described. 'I'he saidbimetal blade i2 is secured at one end to the binding post lt supportedby the panel disc I9 of sheet Bakelite and having a 20 series of holestherein, l9a, as shown, in vertical alignment with and similar to theseries of holes l lc or lb. The said blade l2 is aligned as shownbetween the three series of inlet holes last described and has at itsfree end the contact point 25 ia.

What I term the fixed thermostat, in its application to the round formof my device, comprises the bimetal blade i4 secured and supported atone end by the swivel binding post l5 and hav- 30 ing at its longer freeend Ma the two contact points lib and Mc, its short free end Md, beingbent outwardly, all as more clearly. shown in Fig. 2f The longer freeend lila bends expansibly or outwardly under a rising temperature untilits 35 contact point hib impinges the Contact point Ita upon the end or"the adjustment screw i617 supported in the binding post i6 set in theinsulated panel disc i9. The coil spring I'l serves to normally hold theshort end Idd of the blade lll 40 against the stop post 20 and thisspring also serves as a metallic connection between the post 20 and theswivel binding -post I5. Under a lowering temperature the blade I4 bendscontractively or inwardly and when the ambient atmos- 45 phere reaches apredetermined temperature of say 68 F. the contact point Mb completescircuit thru the contact point I8a in adjustment screw |811 in bindingpost I8 which latter is anchored in the panel disc I9. In the stop post20 50 is an adjustment screw 20a by means of which the contact points Mband Mc are adjusted in any desired spaced relation to all other contactpoints, viz I 2a, I6a, lila. All supporting binding posts are preferablyriveted in position on the panel disc i9 as otherwise the greatvibration set up in the device when actuating would loosen securingnuts.

In the round form of my device I may secure to the upper side of thepanel disc i9 the two blade contacts Zia, 28h, for the reception of theplugs 22a, 22h of the plug 22, which may be of any standard oi' specialdesign and the connecting wires 22e, 22d of which are preferablyconnected in multiple with a distant alarm, signal, annunciator box, orother controlled mechanism designed to perform any usual or specialfunction. The connection to the latter mechanisms may be made thru arelay or transformer thus permitting of employing thru the extensionplug currents of different voltage from that which actuates the multipleaction thermostat.

In the round form of my thermostat I also may employ a metal push button23 supported by the casing ill, the stem 23a being encased in a delicateexpansion coil spring 23h which keeps the ferrule 23o normally pressedagainst the inside of the casing lll and in juxtaposition with the shortfree end Mid of the bimetal blade Ml, as clearly shown in Fig. 2, sothat when the button 23 is manually pressed inward the longer free endlila of the blade l@ is moved with its contact point Mb against thecontact point i511, thus completing the circuit thru the device and allthe mechanisms in the circuit and causing the latter to actuatc. Thisprovides a simple and effective method of testing both the operativenessof the devices in circuit and ascertaining whether the source of supplyis alive.

The rectangular form of my device, as shown in Figs. 4, 5, and 6, issimpler than the round form just described in that it does not embodythe extension plug 22, or the testing button 23, but it is obvious thatthese. elements may readily be added to the rectangular lform. In itsrectangular form a thin partition wall 2li is provided which acts as adivision wall or bale plate in the dissemination of inowing heated airwhen moving at a relatively rapid speed, such as occurs during a fastfire and serves to cause such currents of air assisted by the speciallyarranged inlet openings 25a, 26a, to rst heat the bimetal blade l2sufciently to cause it to move towards and contact with the blade lllbefore the latter is heated sufficiently to cause it to move out of theway. while in the case of a slow accidental fire accompanied by arelatively slow movement of the heated air without and within the casingsuch air is disseminated almost uniformly throughout the casing thuscausing the blade Id to move towards the contact Ilia, and completecircuit therewith before the uniformly moving blade l2 can catch up withand form contact with the blade lll, all as more clearly shown in Fig.5.

The peculiar continual pursuing, in both forms o'f my device, of lthefree contacting ends of the two bimetal blades l2 and Il as hereinbeforedescribed is mostly due to the special arrangement and number of theinlet openings of the casingv which differentially aiect different areaswithin the casing according to the different speeds of movement of theheated air within the casing, all as substantially shown and described.The round form of casing needs no partition wall 2Q because its bladesare oppositely disposed within the casing, while in the rectangularcasing the two blades l2, lli are arranged in close paralielism, andwithout the thin partition 24 both would be similarly affected by thevarying speeds of movement within the casing. The two bimetal blades l2,M, of the rate-of-rise and fixed thermostats are shown in Figs. and 2,respectively, in the positions they assume when factory adjusted at atemperature of '70 F. The casing 25, or rather its body portion, ispreferably formed of an integral Bakelite molding and embodies holes forthe various binding posts, and screws as well as the series of holes25a.

When designed' for closing low voltage currents either my round orrectangular shaped casing may be employed as shown, but when used forclosing currents of over 90 volts then the thermostats would be encasedin a terminal box of any standard approved form.

In instances Where it is desired to employ my improved device as anautomatic thermoelectric detector sounding a separate alarm or signalfor also operating home or other heating units then the contact Mib ofthe round form casing would be spaced so that when the temperature dropsto say 68 F. a separate circuit would be completed'between contacts idband 68a thereby actuating a draft opener or performing more complicatedfunctions. By the use of a step-down transformer householders could runbell wiring to open thedraft door of their small furnaces. butpreferably electricians would make such connections even for small.homes. be donc without in the least interfering with the operation ofthe device as a fire detector and alarm actuator of the multiple actionthermostat type which requires no servicing, which latter objectionbecames serious in installations for small homes where the cost ofperiodical servicing would become a serious objection.

In all instances the casing for the thermostatic blades should be airtight except for the several series of inlet holes, Mb, lla, lila, 25a,25a, and those thru the panel disc GS, and the most efcient arrangement-of such inlet holes can only be obtained thru experimenting upon everychange in the shape of the casing and the location of the twothermostatic blades.

Having described two forms of my multiple action thermostat withparticular reference to their structural features I will now endeavor toelucidate their modus operandi with special ref-b erence to theessential principles involved, including the air directional meansemployed. First, suppose that one of my thermostats ls located at ornear the ceiling of a bed room in a residence or hotel where the doorandwindows are closed, and that an accidental re starts therein. Thensuch re will gain force but slowly because of the lack of an air draftand the heated air will rise and move about the room,

principally at the ceiling, slowly, as likewise within the casings l, 25of my devices and resulting in a nearly uniform distribution of the airtherein. This causes both the fixed and rate-of-rise l bimetal bladesiii, l2, to bend outwardly or toi wards the fixed contact point i60. ata nearly uniform rate until the blade lf3 impinges said contact pointand completes circuit therewith'.v

Next suppose that a fire starts in the sameroom under like conditionsexcept that the door and windows are open, then the initial ame will befanned kwith gathering force into a disastrous conflagration, all as isgenerally well known. Under the last named conditions the now rapid- 1ymoving heated air would enter the casing of my. device thru some of itsinlet openings and All this could pass out through others thus settingup a draft of heated air within the casing with the major volume of theheated air passing in a nearly straight line between the points of thecasing having the larger or more numerous air inlets and causing thebimetal blade I2 of such draft to first become heated and cause it toovertake and make contact with the scarcely moving blade I4. Thesurplusage of heated air would pass around my device. The wells of openstairways are veritable draft creators and these vulnerable pointsshould be protected by locating one of my thermostats upon the ceilingdirectly at the `top of the stairway where a maximum movement of heatedair would pass from rooms and other places below and in which instancemy rate-of'- rise thermostat would generally operate ahead of the fixedthermostat for the reasons given.

A slow or ordinary iire as I have employed the terms herein may bedefined as one in which the temperature rises at the rate of from 1 F.to 4 F. in one minute at the ceiling and where the heated air moves fromone point to another at the speed of from four to twenty yards per`minute. At this slow movement a relatively small volume of the heatedair would, in the case of my round form of device, enter thesmall andwidely spaced inlets IIb, while a considerably larger volume would enterslowly the larger and more numerous inlets IIlband pass upwardly thruthe inlets I9a and out at the inlets llc, or the direction of the slowlyflowing heated air may be reversed. In any event the slow passage ofheated air thru the casing IU would cause it to distribute itself almostuniformly within the casing much as it would be doing in the room wherethe slow fire had started. Under these conditions the bimetal blades I2,I4 would bend in the same direction at a nearly uniform rate and thuspreserve their original spaced relation until the blade I4 was stoppedin its movement by contact with the point I6a when the blade I2 wouldcatch up with it and help hold it in a circuit closing position.

Now a fast rapid or hot accidental re is one during which thetemperature rises from 6 F. to 20 F. per minute accompanied by a heatedair movement of from to 125 yards per minute.

Only a small volume of this rapidly moving heated air can enter thecasing I0 and naturally the greater part of this volume passes thru theinlets Illb, I9a., and IIa in a nearly straight line and it is withinthis line or draft" of heated air that the rate-of-rise bimetal blade I2is located and under which conditions it completes circuit in from oneto five seconds after the starting of a "fast lire.

The rst act of expert firemen upon reaching a fast iire is to stop alldrafts possible while my device induces air drafts within its casing atall times but controls the direction of such drafts in the manner, bythe meansand for the life and property savingv purposes hereindescribed. Y

I claim; y

1. A multiple action thermostat for actuating electrically operatedmechanisms in circuit therewith said thermostat comprising a bimetalblade which acts as a xed thermostat and operates under slow or-ordinaryaccidental ilre conditions at a predetermined temperature for which ithas been adjusted, a secondary quick-acting bimetal air, and means fordirecting said rapidly moving heated air rst and mostly against the saidsecondary bimetal blade. p

2. A multiple action thermostat comprising two bimetal bladesoperatively associated within a casing provided with two sections with athermostatic blade' in each of the casing sections and with air passageslocated in the wall of only one of the sections in a manner todifferentially affect the two blades by varying the direction ofmovement of the superheated air arising from a conagration from theoutside of the cover to the inside thereof under varying accidental fireconditions and whereby one blade closes the operating circuit at apredetermined temperature under conditions produced by a slow orordinary fire, said means also causing the other bimetal blade to actmore quickly thanthe first whenever a relatively fast accidental fireoccurs and sets a relatively fast movement of the heated air fromwithout to within the casing.

3. A multiple action thermostat comprising two bimetal blades supportedwithin a casing provided with two sections with al thermostatic blade ineach of the casing sections and with air passages located in the wall ofonly one of the sections in a manner to differentially affect the twoblades, one of which blades acts independently of the other as athermally operated switch responsive to a relatively slow rate-of-riseand movement of the ambient air caused by a slow or ordinary re when theslow movement of the 4air Within the casing allows the air to beuniformly distributed within` the casing, and means causing the airarising from a relatively fast re to be first and mainly directedagainst or around the second blade and cause it to make a circuitcompleting vcontact withits companion blade before the latter can moveout of contacting relation with said lrst blade.

4. A directional air-drafted thermostat comprising a casing providedwith two sections, air vents in the wall of one of said sections, aprimary -blade in one of the sections and a secondary blade in the otherof the sections, said blades being bendable in the same direction andplane at their adjacent free ends under the influence of heated airentering said casing, the said air vents serving to cause a relativelyuniform distribution of the air entering the casing under conditionsattendant upon a slow accidental fire when the said adjacent free endswill preserve substantially the same spaced relation to each other,while the -said air vents under the conditions of a relatively fast recause the secondary vblade to overtake and form contact with the primaryblade before the latter can move out of the path of movement of vthesecondary blade.

a revolvable support upon which said blade is mounted whereby said bladeis allowed to be pivotally revolved and cause the free end thereof tocomplete a circuit through the device and thus indicate itsoperativeness.

6. In a device of the character described, the' combination with aclosed casing, and a bimetal` blade for controlling electric circuitstogether with a movable post on which itis carried, and means fortesting the operativeness of the circuits consisting of a manual devicein the wall of the casing having a resilient stem adapted to engage theblade and move it,V a pivot revolvably supporting said blade so that thecontact points will operate to complete the circuit and thus indicatethe operativeness of the device wheneverthe resilient stern is pressedinward.

7. In a device of `the class described, the combination of a closedcasing and bimetal blades mounted therein operatively arranged inassociation with each other, and a movable pivot on which one of theblades is mounted so as to have a long arm and a short arm, means forcarrying the other blade at the end thereof, and a push button supportedin theA wall of the casing and having a yielding stem-which engages theshort arm of the blade soas to move the same on its pivot and cause thelong arm to complete the circuit and thereby indicate the operativenessof the devices.

8. A multiple action thermostat, comprising essentially the combinationwith a casing having two diierently ventilated interior sections ofbimetal blades separately arranged in each section and opposite to eachother, means for supporting each of said blades at contiguous ends sothatithe other ends carrying contacts may have free coactive movement inthe same plane.

9. A multiple action thermostat comprising a closed casing having oneinterior section freely ventilated by numerous apertures in the casingthereabouts and a restrictively ventilated interior section contiguouswith the other section; a thermo-active bi-metal blade switch located insaid freely ventilated section proximate to or between said apertures inthe casing said blade switch serving as a quick acting thermostat whencooperatively associated with a secondary thermoactive blade-switchlocated Within vthe said restrictively ventilated section of the casing.

10. A multiple action thermostat comprising a closed casing having'oneinterior section thereof freely ventilated by numerous aperturesthereabouts. in the wall of the casing, and a restrictively ventilatedinterior section contiguous with the other section; a primarythermo-active bimetal blade-switch located in said freely ventilatedsection proximate to and between oppositely disposed apertures in thecasing; a secondary thermo-active bi-metal blade Switch located in therestrictively ventilated section; said bladeswitches moving in the sameplane and preserving substantially the same spaced relation at theirfree adjacent contacting ends under normal or relatively slow movementsof heated air thru or within the casing but making circuit-completingcontact with each other at their free ends Whenever a fast movement ofheated ambient air or relatively rapid rising temperature occurs ,inwhich event a proportionately great amountI of the fast moving heatedair first impinges said primary blade-switch and causes it to flex orbend aroma? towards and against the said secondary blade and completecontact therewith before the latter is caused to move out of the way.

11. A rate-of-rise thermostat, comprising essentially the combinationwith a casing having two differentially ventilated interior sections ofbi-metal blades separately arranged in each section and opposite to eachother, means for supporting each of said blades at contiguous ends sothat the other ends carrying contacts have free co-active movement inthe same plane.

12. The combination vwith a fixed thermostatv having a casing with airpassages therein,ua thermosensitive blade-switch which is freelyventilated by said air passages, of a secondary thermosensitiveblade-switch located in a restrictively ventilated section orcompartment of said casing and having its free contacting endcooperatively associated with the free contacting end of the saidprimary blade-switch.

13. A multiple action thermostat comprising a closed casing havinginterior sections one of said sections being freely ventilated byapertures in the casing thereabouts and a restrictively ventilatedinterior section contiguous with the other section, a thermo-activebi-metal blade-switch located in said freely ventilated sectionproximate to or between said apertures in the casing; a secondarythermo-switch blade mounted in the casing; said blade switches servingas a quick-acting thermostat when cooperatively associated with eachother.

le. A rate-of-rise thermostat comprising a casing said casing having twosections, air ventilating openings in one of the sections forming twodifferentially ventilated sections, bi-metal blades located in each ofsaid sections, means for mounting each of the blades at one of theirends and the other ends being free, and contacts on the free ends of theblades cooperatively associated with each other.-

l5. A rate-of-rise thermostat comprising a casing, said casing having apartition extending substantially the length of the casing forming twosections, air Ventilating openings in one of the sections forming twodifferentially ventilated sections, thermosensitive blades arranged ineach of said sections, means for mounting each of the blades at one oftheir ends, and the other ends being free, and contacts on the free endsof the ,blades cooperatively associated with each other.

16. A rate-of-rise thermostat comprising a closure having two sections,air Ventilating openings in one of the sections thus forming twodifferentially ventilated sections, thermosensitive switches located ineach of said sections, means for mounting each of the saidthermosensitive switches at one of their ends and the other ends beingfree and arranged in contacting relation with each other.

GEORGE HOWLETT DAVIS.

